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Falling-Up Robot Project

I’m developing the Falling-Up Robot, a balancing inverted pendulum bot, using the Teensy 3.6 microcontroller. I want to practice feedback control systems and keep it from falling over. I eventually want it to roam autonomously and let it interact with it environment. I’m building this in stages. So far, the brain and chassis is in place, and the basic balancing control system is in place. It uses a pair of Pololu 90x10mm wheels. Here’s the first video.

https://forum.pjrc.com/threads/41442-Falling-Up-Robot-Project-for-Teensy-3-6?p=133497&viewfull=1#post133497

1 Like

Hello,

Thank you for sharing your project.

Keep up the good work!

-Derrill

@Derrill, how much weight can the Pololu 90x10mm wheels (red) support? My Falling-Up Robot weighs about 10 pounds.

Also, the stepper motor shaft diameter is 0.25", so I use the Pololu Universal Aluminum Mounting Hub. I found it difficult to center the Pololu wheel to the mounting hub, so there’s a bit of wobble when the robot travels. Can you recommend a method of installation or a different product that improves centering? Thank you.

Those wheels should be fine with your 10 lbs load; however, you might check your motor specifications to see if they can handle a radial load that high.

It is difficult to say what might be happening with your wheels and hubs from your description. Can you post a picture showing how you have those hubs and wheels mounted? Also, can you post a video showing the wobble?

You can see how those wheels should be attach to those hubs in the following picture.

-Derrill

The hub was attached as shown in your picture. My issue is that the holes in the wheels for the #4-40 bolts are somewhat over-sized, so there’s a bit of radial freeplay. It’s difficult to center the hub with the wheel. The effect is wobble and it’s difficult to see it in a video.

I’m very interested in your Scooter/Skate Wheel and 0.25" Aluminum Scooter Wheel Adapter. How much radial freeplay is there between the two? I’m hoping centering will be more automatic.

Hello.

The machined aluminum adapter components (which we identify with dev codes: dwa01a, dwa01c, dwa01d and dwa01e) press fit tightly into the hubs of scooter wheels. So, we do not expect centering the gearmotor shafts within the scooter wheels to be an issue.

-Jon

Okay, I got the XBEE communication working with the Teensy 3.6 mcu, and able to send motion commands to the Falling-Up Robot. Able to yaw and translate the 6-foot robot while maintaining tilt stability. It’s no longer tethered to the USB port and the power supply unit. See latest video below. Recommend headphones.
https://www.youtube.com/watch?v=QHb9eYAyGJc

That’s pretty stable; it looks like the Pololu wheels and hubs worked out okay. Thanks for sharing!

-Jon

Hi.

We posted about your robot on the Pololu Blog. Thanks for sharing!

Ryan

Thank you very much.

E.V.L.